Membrane contactors are devices used to, among other things, degas liquids. For example, membrane contactors may be used to degas boiler water.
Membrane contactors typically operate on a diffusion principle. Hollow fiber membrane contactors typically have a shell side and a lumen (or tube) side, and these sides are separated with a membrane, for example, a microporous membrane. In operation, the gas-entrained liquid is introduced into one side of the contactor, while vacuum or a combination of vacuum and sweep gas or a gas depleted liquid is passed through the other side. As the liquid passes through its side, the gas diffuses across the membrane into the other side.
Such membrane contactors are known, for example, see: U.S. Pat. Nos. 5,264,171; 5,352,361; 5,186,832; 5,284,584; & 5,695,545, each of which is incorporated, in its entirety, herein by reference. For example, in FIG. 1 (FIG. 7 from U.S. Pat. No. 5,264,171), gas-entrained liquid enters the contactor at inlet 15, exits the perforated center tube 12, flows over the exterior surfaces of the hollow fibers 1 (the gas-entrained liquid is degassed as it passes over the hollow fibers) and around the baffles 20a/b, back into the perforated tube 12, and exits the contactor via outlet 17 (this is a shell side path). As the liquid is passing over the hollow fibers, the lumens of the hollow fibers are evacuated (vacuum) or subject to vacuum and sweep gas introduced via inlets 18/19. These are excellent contactors and such Liqui-Cel® brand contactors are available from the Membrana—Charlotte Division of Celgard, LLC of Charlotte, N.C. The configuration, i.e., with the inlet 15 and outlet 17 at opposite end of the contactor, can limit the placement (or piping configuration) of the contactor for certain applications.
Accordingly, there is a need for a membrane contactor that can be easily used in limited spaces.